An Aussie saddle with the traditional panel bottom only needs a thin saddle towel between it and the horse. You can ride without even that, but you will have to clean the panels occasionally and it creates more wear on them.
If you need a "supportive" saddle pad then you are not using your Aussie saddle for what they are designed for- security and comfort for both horse and rider
If the panels aren't fitting your horse, then you need to adjust them to fit by awling (search that term here for my explanation)
Thank you both for your input. The Fleeceworks products look beautiful!
Spookhorse, I didn't realize the pad could be thinner. I've never had an aussie with the serge panels before. It does fit him quite well and so thats good news that I can use a lighter pad. I always had the concept that one protected the back under the "bar" area (as in western) or with a half pad.